An important feature of contemporary cellular wireless networks is the ability to locate the geographical position of a mobile station. This capability was initially developed to assist emergency services in locating mobile stations. However, the availability of position information to support 911 services has given rise to the development of many other location-based-service (LBS) applications as well.
For instance, given the position of a mobile station, an LBS provider (e.g., a wireless service provider or third party) can provide the mobile-station user with a weather or traffic report pertaining to the user's vicinity. As another example, an LBS provider can report a list of services or establishments (e.g., restaurants, parks, or theatres) in the user's vicinity. As still another example, an LBS provider can provide a mobile-station user with a map of the user's position and/or with directions for travel between the user's position and another location. As yet another example, knowing that a mobile station is operating in a particular position, an LBS provider can send the mobile station a location-based message, such as an advertisement or coupon for a nearby establishment. Other LBS applications exist currently, and more will surely be developed in the future.
In practice, when an LBS application wants to determine the position of a mobile station, the application may send a position-determining request message to the wireless carrier that serves the mobile station. In response, the carrier may then send a signaling message through its network to determine where the mobile station is currently located. A position-determining platform operated by the wireless carrier or a third party vendor may assist in the position-determination. After determining the position of the mobile station, the wireless carrier may then generate a response to the position-determining request and send that response to the LBS application.